There are a wide variety of couplers/couplings used to interconnect fluid conveying lines. Many couplings are designed to handle special safety requirements. Particularly for fluid lines that convey fuel, there are safety requirements that require a coupling that interconnects the lines be capable of conducting electrical charge through the coupling to ensure that an electrostatic charge does not build up on one of the coupled sections of the lines. It is well known that a stored electrostatic charge can give rise to the hazard of an electrical spark in the presence of vaporized fuel. Discharge of the spark by grounding, or by flexing of the coupling that may bring metallic parts of the coupling into contact with one another may result in instantaneous combustion of vaporized fuel. This combustion can in turn cause ignition of the fuel conveyed in the lines, resulting in a catastrophic fire or explosion. Buildup of electrostatic charge by ionization of fuel as it is conveyed through the lines continues to be a concern for all fuel lines, especially within aircraft. Lightning strikes can also generate spark, and such strikes may be referred to as a dynamic cause of electrical charge. Thus, a coupler used within a system of fuel conveying lines must have the capability to dissipate all types of electrical charges that may be present. Particularly for lightning strikes, it is important that the coupler have the ability to quickly dissipate electrical charge due to the potential magnitude of a spark caused by the lightning strike.
Most coupler designs presently utilize metallic flanges that are sealed to the coupler by deformable O-rings. Because O-rings are typically made from a non-conductive material such as rubber or rubber compounds, the O-rings electrically insulate the coupled sections of the lines from each other. Therefore, any ionization of fuel that flows through the lines can give rise to differential electrostatic charges between the coupled sections. There remains a need to ensure electrical conductivity across coupled sections of fuel lines to prevent electrostatic buildup considering the continued use of O-rings in modern coupler designs.
There are various types of known electrical jumpers, also referred to as bonding jumpers or bonding rings, used to eliminate the hazard of differential electrostatic charges. In short, a bonding jumper provides an electrically conductive connection between the coupled sections of a fluid line to prevent or limit buildup of electrostatic charges within the coupler. Bonding jumpers can be generally categorized within two types, namely, exteriorly mounted jumpers and interiorly mounted jumpers. For exteriorly mounted bonding jumpers, these may require some degree of assembly and disassembly, which therefore makes exteriorly mounted jumpers more difficult to use. For interiorly mounted jumpers, these may include various forms of electrical conductive material such as springs or wires that are retained within the coupling placed in intimate contact with the coupled flanges of the fuel lines, thereby maintaining electrical conductivity between the flanges of the fluid conveying lines. One particular disadvantage of many types of interiorly mounted bonding jumpers is that there is no means to visually inspect whether the bombing jumpers are properly positioned to make from contact with the flanges. Another disadvantage to these interiorly mounted jumpers is that the jumpers cannot be modified or replaced, since they typically are permanently mounted within the coupler.
Examples of exteriorly mounted jumpers include those disclosed in U.S. Pat. Nos. 4,008,937; 4,346,428; 4,881,760; 4,900,070; 5,188,400; and 5,620,210.
Examples of interiorly mounted jumpers include those disclosed in U.S. Pat. Nos. 4,487,462; 4,808,117; 5,959,828; 6,880,859; 6,883,836; and 7,222,889.
Another method of preventing buildup of electrostatic charge may include use of conductive coatings applied to a coupling assembly and/or to the flanges of the fluid conveying members. Examples of references disclosing conductive coatings include the U.S. Pat. Nos. 5,786,976 and 5,959,828.
Despite the numerous available designs for bonding jumpers, there still a need to provide a bonding jumper that can be used to handle wide ranges of electrical amperages that may be present, as caused by numerous sources of electrical charges, to include both passive and dynamic sources. There is also a need to provide a bonding jumper that is easy to install, and can be used to supplement an existing bonding jumper capability for those couplers it may have an integral bonding jumpers.